Department of Environmental Science and Engineering, College of Environment and Resources, Xiangtan University, Xiangtan 411105, China.
Department of Environmental Science and Engineering, College of Environment and Resources, Xiangtan University, Xiangtan 411105, China.
Ecotoxicol Environ Saf. 2021 Dec 20;227:112880. doi: 10.1016/j.ecoenv.2021.112880. Epub 2021 Oct 13.
Phosphorus (P) containing minerals are identified as effective Pb stabilizers in soil, while their low solubility limit the Pb immobilization efficiency. In this work, the combination of phosphate solubilizing fungi (PSF) Penicillium oxalicum and tricalcium phosphate (TCP) was constructed and applied to improve Pb immobilization stabilities in medium and soils. P. oxalicum+ TCP could significantly improve Pb removal to above 99% under different TCP/Pb and pH values. TCP and P. oxalicum could remarkably immobilize Pb by ion exchange, and PbCO precipitation or surface adsorption, respectively. While the enhanced Pb immobilization in P. oxalicum+ TCP was explained by stronger Pb interaction with tryptophan protein-like substances in extracellular polymeric substance, and the formation of the most stable Pb-phosphate compound hydroxypyromorphite (Pb(PO)OH). Toxicity characteristic leaching procedure test showed that only 0.91% of Pb was leachable in P. oxalicum+ TCP treatment, significantly lower than that in P. oxalicum (2.90%) and TCP (7.52%) treatments. In addition, the lowest soil exchangeable Pb fraction (37.1%) and the highest available soil P (88.0 mg/kg) were both found in P. oxalicum+ TCP treatment. By synergistically forming stable Pb-containing products, thus the combination of PSF and P minerals could significantly improve Pb immobilization and stability in soils.
含磷矿物被鉴定为土壤中有效的 Pb 稳定剂，但其低溶解度限制了 Pb 的固定效率。在这项工作中，将解磷真菌（PSF）草酸青霉和磷酸三钙（TCP）组合使用，以提高中温和土壤中 Pb 的固定稳定性。在不同的 TCP/Pb 和 pH 值下，P. oxalicum+TCP 可显著提高 Pb 的去除率，达到 99%以上。TCP 和 P. oxalicum 可通过离子交换、PbCO3 沉淀或表面吸附分别显著固定 Pb。而在 P. oxalicum+TCP 中增强的 Pb 固定作用可归因于 Pb 与细胞外聚合物中色氨酸蛋白样物质的更强相互作用，以及形成最稳定的 Pb-磷酸盐化合物羟磷铅矿（Pb(PO)OH）。毒性特征浸出程序测试表明，在 P. oxalicum+TCP 处理中，只有 0.91%的 Pb 是可浸出的，明显低于 P. oxalicum（2.90%）和 TCP（7.52%）处理。此外，在 P. oxalicum+TCP 处理中，土壤可交换态 Pb 含量最低（37.1%），有效土壤 P 含量最高（88.0 mg/kg）。通过协同形成稳定的含 Pb 产物，因此 PSF 和 P 矿物的组合可以显著提高土壤中 Pb 的固定和稳定性。
